Before you start thinking if the "activity" in bad, it would be good, (as Davidcpa suggests) to find out what kind of scan it was and where the activity is located. Maybe you or his primary caregiver could find out if you don't already know. When my son had a CT scan and an area of concern showed up on his lung, I was a basket case of worry but it turned out just to be scar tissue from pneumonia that he had previously. Right now you don't know if it's bad or not, so try not to worry, keep busy and get back to us so we can know what's happening.